Dominic Mohan, editor of the Sun newspaper, arrives to give evidence at to the Leveson inquiry at the Royal Courts of Justice in London on February 7, 2012. Photograph: Getty Images.

With rather unfortunate timing, the Sun has been forced to apologise for illegally accessing text messages on Labour MP Siobhain McDonagh's stolen phone. The paper, which is not accused of the theft of the phone itself, also paid damages of £50,000. The Sun's QC Dinah Rose QC told the judge: "Through me [the Sun] offer their unreserved apology to the claimant for what has happened.

"Furthermore they have undertaken to the court not to use any information so obtained nor to access or attempt to access by unlawful means the claimant's private information."

What makes the story particularly significant is that the phone was stolen in October 2010 after Dominic Mohan, the current editor, took up his post. In response, Labour MP and shadow immigration minister Chris Bryant has called for Mohan to be sacked.

Bryant and Watson will be dismissed as the usual suspects by News International but it is likely that at some point Mohan will be forced to account for what he knew when.

Depending on your perspective, the case can be cited as evidence either for or against tougher press regulation. There are already laws against hacking and, on this occasion, they have been appropriately applied. But this latest incident does undermine the claim that the industry is self-correcting itself. Only state-backed regulation, some will argue, can enable the necessary culture change.